Low-power electrical stimulation has been found to have various therapeutic uses. One example of low-power electrical stimulation is transcutaneous electrical nerve stimulation (“TENS”). TENS devices typically operate by generating low-power electrical impulses that are supplied to the skin of a patient through electrodes. The electrical impulses have been found to diminish or completely relieve pain previously felt by a patient.
There are two primary theories for the effectiveness of TENS devices. The first theory is the Gate Control Theory. In this theory, the mild electrical stimulation is thought to relieve pain in a similar way as when an injured area is manually rubbed. Rubbing acts to mask the pain from the injury. Similarly, when electrical impulses pass through the skin they pass through portions of the peripheral nervous system. The electrical impulses reduce the transmission of pain messages, thereby diminishing or completely relieving pain.
A second theory is the Endorphin Release Theory. This theory states that the electrical impulses from the TENS device cause mild to moderate muscle twitching in the body. The body responds to the muscle twitching by producing natural pain relievers called endorphins, thereby diminishing or completely relieving the pain.
In addition to TENS, electrical stimulation has also been found to be useful for other therapies. Examples include edema reduction, wound healing, iontophoresis drug delivery, muscle stimulation, and interferential current therapy.